java中的this关键字用于引用当前对象或类的实例。它可以在构造函数中用于调用任何其他重载的构造函数,但这个关键字应该是构造函数中的第一条语句。
this 关键字可用于引用类的实例变量。
package org.arpit.java2blog; public class Employee { String name; int age; public Employee(String name,int age) { this.name=name; this.age=age; } public void workOnAssignment() { // Working on assignment } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public static void main(String args[]) { Employee e1=new Employee("John",20); System.out.println("Employee's name : "+e1.getName()); System.out.println("Employee's age : "+e1.getAge()); } }
当你运行上面的程序时,你会得到下面的输出:
Employee’s name : John Employee’s age : 20
如您所见,我们使用这个关键字在构造函数中设置实例变量的值。
如果你想调用同一个类的重载构造函数,你可以使用这个关键字来做到这一点。 例如:
package org.arpit.java2blog; public class Employee { String name; int age; public Employee() { System.out.println("Calling No arg constructor"); } public Employee(String name,int age) { this(); System.out.println("Calling Parameterized constructor"); this.name=name; this.age=age; } public void workOnAssignment() { // Working on assignment } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public static void main(String args[]) { Employee e1=new Employee("John",20); System.out.println("Employee's name : "+e1.getName()); System.out.println("Employee's age : "+e1.getAge()); } }
Calling No arg constructor Calling Parameterized constructor Employee’s name : John Employee’s age : 20
请注意,用于调用另一个构造函数的 this 关键字应该是该构造函数中的第一个语句。
package org.arpit.java2blog; public class Employee { String name; int age; public Employee(String name,int age) { this.name=name; this.age=age; } public void workOnAssignment() { // Working on assignment } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Employee getEmployee() { return this; } public static void main(String args[]) { Employee e1=new Employee("John",20); Employee e1Copy=e1.getEmployee(); System.out.println("Employee's name : "+e1Copy.getName()); System.out.println("Employee's age : "+e1Copy.getAge()); } }
Calling No arg constructor Employee’s name : John Employee’s age : 20
这就是java中这个关键字的全部内容。
原文链接:https://codingdict.com/